This section provides background information related to the present disclosure which is not necessarily prior art. This section also provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
Bearing temperature rise is a good indicator that a bearing is not working at optimum conditions. A rise in temperature can be caused by many factors, but the result is degradation of the bearing useful life.
Previously, bearing temperature measurements were made using a thermocouple. A thermocouple uses dissimilar metals to conduct a signal. This signal is read back through a device that converts the signal to a temperature. The signal works with the difference in resistance between the two dissimilar metals. As the temperature changes, the resistance changes. Given two known temperatures and resistances, a linear relationship can be created between the resistance and the temperature. The reading device will convert the resistance to temperature based on these values.
Another conventional solution includes imbedding a temperature sensor into the casting of a mounted bearing. The sensor gives a linear relationship between the bearing temperature and a 4-20 mA electrical signal. The solution is meant, like the thermocouple, to attach to an external source for power and for temperature indication.
Both of these prior solutions have certain limitations. The thermocouple and embedded sensor both require external power input. Some bearing applications are not in a position where external power inputs can be easily brought to the bearing mounting location. This issue often leaves these bearings vulnerable to failure without maintenance personnel having sufficient warning. Should a failure like this happen, damage to the bearing and surrounding equipment may occur.
To alleviate this issue, some have employed a visual indicator that will alert if the bearing temperature reaches a certain point. The temperature is monitored through sensing equipment that runs on a power supply. The power supply is either an external power supply that must be brought in, or a battery power supply housed in the visual indicator unit. If the power is supplied by the batteries, a life limitation is put on the unit. The unit can only take measurements for a given period before the batteries run out of power. To mitigate this issue, previous attempts were used to incorporate a timer into the system. The user can set the unit to only take a reading at a certain interval. Although this does increase the life of the product, the life is still limited by the useful life of the battery power source.
According to the principles of the present teachings, a bearing temperature monitoring system is provided that alerts a user when the temperature of a bearing has reached a predetermined level. That is, the indicator device of the present teachings provides a clear status indicator that a bearing has reached a temperature that is undesirable in the application. It should also be recognized that the principles of the present teachings can also be used to indicate other, perhaps desired, temperatures. Because this bearing temperature monitoring system has an internal power supply in some embodiments, it requires no outside power system to be provided. The sensor component is capable of reacting to a temperature change without the need for applied power. Therefore, the internal power supply is essentially only used during an alert period. The indicator device of the present teachings is further compatible with existing bearing housing designs and, thus, does not require any additional modifications. Because no modifications to the housing are required, the indicator device of the present teachings can be retrofitted to products currently in use or marketed.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.